Which GPA do colleges look at?

Usually they are looking at your ulative GPA from your transcript, but most colleges will weight your GPA using their own formula. That gives you extra credit for AP, IB or Honors cles. If they are comparing applicants with borderline GPAs (by their standards), they will also be likely to favor someone whose grades improved over their last couple of semesters vs. someone who slipped a little at the end.